System for vaporizing oil

ABSTRACT

The invention is directed to a system for vaporizing oil and mixing it with hot air to form a combustible oil vapor-air mixture. Controls are provided to maintain a desired vapor-air ratio.

United States Patent [191 Feng [451 May 27, 1975 SYSTEM FOR VAPORIZING OIL [75] Inventor:

[73] Assignee: Selas Corporation of America, Dresher, Pa.

22 Filed: Mar. 1, 1974 21 Appl. No.: 447,161

Chung Liao Feng, Radnor, Pa.

[52] US. Cl. 431/11; 431/l15;431/161; 431/215 [51] Int. Cl. F23d 11/44 [58] Field of Search 431/10, 11, 161, 215, 217, 431/2, 8, 9,115,116

[56] References Cited UNITED STATES PATENTS 3,052,287 9/1962 Shirley 431/10 X 3,228,451 1/1966 Fraser et a1.. 431/10 3,614,282 10/1971 Gabor 431/11 X Primary ExaminerEdward G. Favors [57] ABSTRACT The invention is directed to a system for vaporizing oil and mixing it with hot air to form a combustible oil vapor-air mixture. Controls are provided to maintain a desired vapor-air ratio.

4 Claims, 1 Drawing Figure SYSTEM FOR VAPORIZING OIL SUMMARY OF THE INVENTION The present invention relates to combustion, and more particularly to a method and apparatus for vaporizing a liquid hydrocarbon and supplying the vapor to a furnace or other equipment in which it is combusted.

In order to burn oil in those installations which require short flame burners or which require close control of the fuel-air ratio, it is necessary first to vaporize the oil and supply the vapor to the point of combustion. This procedure has the disadvantage that vaporized oil is not a fixed gas and will condense if permitted to cool below a particular point, depending upon the fuel being used. Because of this, special precautions must be used to keep the vapor above the condensing temperature until it is used.

The system of the present invention is adapted for use with any type of installation, using oil as a fuel. It is specifically adapted, however, for jobs using open burners that must be accurately controlled. The system makes use of a separate oil-fired air heater for vaporizing the oil used directly as fuel. Various controls are applied to the system to insure that the oil is completely vaporized and mixed with air to form a combustible mixture. The oil is kept in a vaporized condition until used.

In practicing the invention there is provided a heater in which sufficient oil is burned to produce hot products of combustion to vaporize the fuel oil supply. These products of combustion are heated above oil vaporization temperature and are mixed with air to heat it. The oil fuel is injected into this gas stream, vaporized, and carried thusly to the point of use. Ordinarily, the air when mixed with the vapor is sufficient to make a combustible mixture that will burn with the characteristics of gas.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

IN THE DRAWINGS The single FIGURE of drawing shows diagrammatically the elements of the system and their relation to each other.

DETAILED DESCRIPTION Referring to the drawing, there is shown a structure forming a hollow combustion chamber 1 in which combustion takes place of fuel and air supplied by a burner 2. The air for combustion is supplied under suitable pressure from a blower 3 through a duct 4. The duct has a portion 5 partially surrounding chamber 1 so that the air flowing to burner 2 will be somewhat preheated. The volume of air is controlled at some desired amount by means including an orifice plate 6 in duct 4. Differential pressure across the orifice is applied to a conventional flow controller 7 which produces adjustment of a valve 8 in the duct. Thus, the volume of air supplied to burner 2 can be regulated by adjustment of controller 7.

Oil or fuel for burner 2 is' supplied from a tank 9 through a pipe 11 by a variable speed pump 12.

Hot products of combustion are discharged from the combustion chamber through a discharge duct 13 where they are mixed with air supplied by blower 3 through a duct 14. The temperature of the mixture of products of combustion and air in duct 13 is controlled to a desired value. To this end the temperature thereof is measured by a temperature sensitive element such as a thermocouple 15. The response of this thermocouple is applied in a conventional manner to produce a variation in the speed of pump 12 and therefore the volume of oil supplied to burner 2. In this manner the temperature of the gases in duct 13 can be adjusted.

The hot products of combustion in duct 13 are mixed with air supplied by blower 3 through a duct 14. This mixture is kept at a desired temperature, asindicated above, which is high enough to vaporize the oil fuel being used. Generally this temperature will be between 600 F and 800 F. The heated air and products of combustion pass into a vaporizing and mixing chamber or zone 16, from which they move to the point of'use. Oil to be vaporized is injected into chamber 16 by a pipe 17. Oil is pumped through the pipe by a motor 18 from the tank 9.

The amount of air supplied to duct 13 and chamber 16 is sufficient to form a combustible mixture with the vaporized oil injected from pipe 17. Since varying amounts of oil of different kinds may be vaporized by the system, it is necessary to monitor the mixture. To this end, a conventional calorimeter type of apparatus 19 burns a sample of the mixture of vaporized oil and air, and, in response to the characteristics of the mixture operates to adjust a valve 21 in duct 14 to keep the air-oil ratio at some desired value so that the desired type of combustible mixture is produced.

The system is adapted to use all hydrocarbons that can be completely vaporized before they start to crack. As a summary, oil and air are burned in a combustion chamber to produce hot products of combustion in sufficient volume and at a high enough temperature to heat air for combustion sufficiently to vaporize oil fuel. This temperature is normally between 600 F. and 800 F for No. 2 fuel oil and will cause almost instantaneous vaporization of the oil and mixing with the air. As the mixture is conveyed from mixing chamber 16 to the point of use, it should never drop below a temperature where the oil will condense, for example, 315 F. for No. 2 oil.

When the system is started, hot products of combustion from burner 2 are discharged through the system down stream of Chamber 1 for as long as it takes to achieve a temperature of about 500 F in the ducts to be contacted by the mixture to the point of use before oil in pipe 17 is discharged into chamber 16. This is to prevent any possibility of the oil condensing before the system is in operation. Conversely, the temperature of the oil vapor-air mixture should not be too high since when stoichiometric oil vapor-air mixtures are heated above 700 F. the oil starts to crack. It has been found that keeping the mixture at about 500 F. results in very satisfactory combustion.

While in accordance with the provisions of the Statutes l have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is: 1. The method of preparing a liquid hydrocarbon for combustion which comprises:

burning fuel and air to produce hot products of combustion, mixing a supply of additional air with said products of combustion, regulating the supply of fuel to maintain the mixture of additional air and products of combustion at a temperature above the temperature of vaporization of said liquid hydrocarbon, injecting liquid hydrocarbon into said hot mixture thereby to vaporize the hydrocarbon and form a vapor-air mixture, and adjusting said supply of additional air to obtain a ratio of air to vapor so that the vapor-air mixture is combustible. 2. The method of claim 1 including measuring the temperature of the mixture of products of combustion and additional air and adjusting the supply of fuel in response to said temperature.

3. The method of claim 1 including burning a sample of said oil vapor-air mixture and adjusting the supply of air in response to a condition produced by said burning.

4. Apparatus for vaporizing a liquid hydrocarbon comprising means forming a combustion chamber, a burner firing into said chamber, a discharge from said chamber for products of combustion, means to supply fuel and air to said burner, means to measure the temperature of the products of combustion, means to supply air to mix with said products of combustion, the mixture flowing to a vaporization chamber, means to inject liquid hydrocarbon into said mixture in said vaporization chamber, means responsive to said temperature measuring means to adjust said fuel supply to said burner to maintain the temperature of said mixture above the vaporization temperature of said liquid hydrocarbon. 

1. THE METHOD OF PREPARING A LIQUID HYDROCARBON FOR COMBUSTION WHICH COMPRISES: BURNING FUEL AND AIR TO PRODUCE HOT PRODUCTS OF COMBUSTION, MIXING A SUPPLYING OF ADDITIONAL AIR WITH SAID PRODUCTS OF COMBUSTION, REGULATING THE SUPPLY OF FUEL TO MAINTAIN THE MIXTURE OF ADDITIONAL AIR AND PRODUCTS OF COMBUSTION AT A TEMPERATURE ABOVE THE TEMPERATURE OF VAPORIZATION OF SAID LIQUID HYDROCARBON, INJECTING LIIQUID HYDROCARBON INTO SAID HOT MIXTURE THEREBY THE VAPORIZE THE HYDROCARBON AND FORM A VAPOR-AIR MIXTURE, AND
 2. The method of claim 1 including measuring the temperature of the mixture of products of combustion and additional air and adjusting the supply of fuel in response to said temperature.
 3. The method of claim 1 including burning a sample of said oil vapor-air mixture and adjusting the supply of air in response to a condition produced by said burning.
 4. Apparatus for vaporizing a liquid hydrocarbon comprising means forming a combustion chamber, a burner firing into said chamber, a discharge from said chamber for products of combustion, means to supply fuel and air to said burner, means to measure the temperature of the products of combustion, means to supply air to mix with said products of combustion, the mixture flowing to a vaporization chamber, means to inject liquid hydrocarbon into said mixture in said vaporization chamber, means responsive to said temperature measuring means to adjust said fuel supply to said burner to maintain the temperature of said mixture above the vaporization temperature of said liquid hydrocarbon. 